Dietary restriction (DR) is a powerful intervention, which slows the aging process and increases the lifespan of organisms, from yeast to mammals. The TOR signaling pathway is an evolutionarily conserved pathway implicated in the control of aging, and TOR is necessary for the full effect of DR. Hi95 /sestrin2 is a negative regulator of TOR pathways in mammals and invertebrates. We have found that Hi95/sestrin2 expression is significantly reduced in the brain, muscles and liver of BMAL1-deficient mice, and is increased in the same tissues of CRY-deficient mice; furthermore, BMAL1 deficiency results in up regulation of TOR signaling, suggesting that BMAL1 is a negative regulator of the TOR pathway. BMAL1 and CRYs are components of the circadian clock system. Thus, our preliminary data suggest a previously unknown interaction between the TOR signaling pathway and the circadian clock which may explain the role of the circadian clock in aging. We hypothesize that DR regulates the activity of the circadian clock proteins BMAL1 and CRYs, and these proteins mediate the effect of DR on longevity through the regulation of TOR pathways. We will address this hypothesis through the following Specific Aims: Aim 1. To study the molecular mechanisms of regulation of BMAL1 transcriptional activity by glucose. Aim 2. To investigate the role of the circadian clock proteins in the regulation of the Hi95-mTOR pathway. Aim 3. To study the role of the circadian clock and circadian clock proteins BMAL1 and CRYs in dietary restriction.